Written by Michael Linden , Center for American Progress Republican presidential candidate Newt Gingrichs tax plan is so extremeand so unfair to the middle classthat its almost impossible to believe that it comes from a serious presidential candidate from a major political party. For starters, it would cut taxes for the super-wealthy by so much that the normal adjectives (dramatically, massively, enormously) dont even apply. At the same time, it would introduce a new level of complexity for many middle-class families who would have to calculate their tax bill twice each year to figure out how much they owe. But thats not all. Gingrich would slash the corporate income tax rate down to historically low levels while keeping in place every existing corporate tax loophole and special tax break. The plan would result in the lowest levels of federal revenue in 70 year...